Ye Qing Huan moved back when he approached the Kunlun Sect disciples.
She had the barrier up, so it wasn't as if they would be able to detect her even if she stood by Lin Fan's side. But it was better to be safe than sorry when it came to things like this.
At the same time, Lin Fan could feel the killing intent that was coming from Ye Qing Huan.
It was very clear what she wanted to do to these disciples from the Kunlun Sect.
The only reason that she hadn't done anything yet was because she was being cautious. She didn't know if they had planned anything with the embryo if she were to do anything to them.
As such, she didn't make a move until she was certain that the embryo was destroyed.
As for how the embryo would be destroyed, that was actually up to Lin Fan.